When a vehicle is stopped on an incline, vehicle rollback may occur between release of a brake pedal and depression of an accelerator pedal. To conserve fuel and energy, a hybrid vehicle turns off an engine by cutting fuel delivery while a vehicle is stopped. The driver resumes vehicle travel by releasing the brake pedal and depressing the accelerator pedal. Typically, the engine is not restarted until the end of a brake pedal release stroke when the brake has been fully released. When the hybrid vehicle is stopped on an incline, a certain amount of brake pressure is necessary to hold the vehicle on the incline. During the brake pedal release stroke, prior to restarting of the engine, the brake pressure may become insufficient to hold the vehicle on the incline and vehicle rollback may occur.
Similarly, vehicle rollback may occur in a conventional powertrain vehicle which utilizes a neutral-idle mode. A transmission in such a vehicle is moved to neutral while the vehicle is stopped to conserve fuel and reduce idle vibration. When the vehicle is stopped on an incline, the vehicle is held by a brake system. Typically, the vehicle exits the neutral-idle mode and engages a vehicle clutch at the end of the brake pedal release stroke. Vehicle rollback may occur prior to the vehicle exiting neutral idle mode when the brake pressure is no longer sufficient to hold the vehicle on the incline.